I’m sitting here watching The Day After. Right before the bomb dropped down, the movie shows a bunch of panicked people trying to get their stalled vehicles to work. The cars just stopped working and then KA-BLOOEY!! Would this really happen? If so, what would cause it?
Engines (or rather, the electronics and electrical systems needed to run them) can be disabled by an EMP (electromagnetic pulse) generated by an airbusrt nuclear explosion. Basically, the EMP induces large surge currents in circuitry which burns it out. However, this happens after the explosion, not before. And it only happens to any significant degree in an airburst detonation. Ground bursts and subterranean explosions don’t cause EMP, despite what the film Broken Arrow would have you believe.
Isn’t the metal body of the car going to act as a sort of Faraday cage?
In The Day After, the Sovs lobbed a couple of orbital bursts for EMP before the rest started hitting targets.
Nope. Unlike an electric field, a magnetic field cannot be entirely blocked by a proper Faraday cage. Cars are far from an effective cage, in any case. The best you can do is attenuate it, and even then only if the shield is a good “conductor” of magnetism (in magnetics, we say it has a high permeability, aslo called mu), and has no large gaps in it. Cars with all-steel bodies would have a fairly high mu, but these are becoming increasingly rare in these days of lightweight nonmetallic composites, and besides, with the large windows, you’re pretty boned anyhow.
Replace all the solid-state electronics with tubes and you might have a shot. Just ask the Russians.
Monstro, without hijacking your thread, can I ask VunderBob for an explanation of why they’d do this? It sounds pretty brilliant really… is it to halt the sequences in place by the military for bunkering and, then, retaliation? EMPs to halt everything from blast doors shutting to the launch of strike aircraft, minuteman missles, etc? I’m assuming the EMP would be strategically feasible since it would have a much farther reaching effect than simple nuke blast dynamics?
Cars are faraday cages with holes in them. It doesn’t take much to shut them down:
Not so much military, which is hardened against EMP (somewhat) as much as civilian electronics. A couple of high-altitude air bursts would set all communications and electronics in the US on “burble.” No communication+no co-ordination= Bad Things for the Good Guys. It would also turn every civilian airliner into a multimillion dollar brick.
This document gives a good description of what you can accomplish with a single nuke in space:
Achilles’ Heel: Space and Information Power in the 21st Century
So is it true the Soviets had redundant electronics systems made with vacuum tubes in they’re bombers?
Did we have that?
You sure about that? Surely they do generate an EMP but the EMP is absorbed by the surrounding material?
The MiG-25 a defector brought to Japan was equipped with vacuum tubes.
No. The EMP isn’t generated by the nuke directly, but by its gamma rays interacting with the atmosphere. Subterranean nukes have all their gamma absorbed before it gets out into the air. There’s a nice essay here: Yahoo | Mail, Weather, Search, Politics, News, Finance, Sports & Videos
No. The EMP is generated by high energy particles from the blast ionising a huge area of the upper atmosphere. The free electrons start oscillating in the earths magnetic field. It is this oscillation that produces the EMP over a wide area. In the lower atmosphere/ground burst those high energy particles are busy actually heating up material to ionise it, and the density is higher so the volume of ionisation is smaller. There is an effect from direct high energy particles from a nuclear blast on electronics, but if you are that close to the blast, EMP is the least of your worries.
ETA: What matt said. The wikipedia article covers this as well.
Si
With the gamma rays, there is also a significant risk of Hulkism.
Not exactly. The vacuum tubes weren’t redundant systems, they were the airframe’s main systems.
The initial reaction of Western observers after they inspected Belenko’s plane was scorn - “they’re still using vacuum tubes?!?”- the West having long since moved on to solid-state electronics.
Then they thought about it a little bit, and said “Wait… you don’t think they’re planning for EMP… do you?”, which as it turned out, they were.
Older, mechanically injected, Diesel engines are immune to EMP. An old car with a carburetor and Kettering ignition (mechanical points) would probably be fine as well. Modern engines, most diesels included, have electronic controls that would not survive.
In Russia, electronics burst YOU!
In the book War Day, the STARTERS on most cars built since around 1965 wouldn’t work after EMP hits, despite the fact that the engines would by and large have worked on many cars built prior to the 1980s.
Nah, starters have excellent magnetic shielding, and fields sufficient to saturate the iron they contain won’t overvoltage the windings. (that is pretty much thier normal operating condition) What DOES approximately fit that vintage, though, is the change from generators, to alternators. Alternators have diodes that could well be susceptible to EMP.